Catheter retention

ABSTRACT

A multiple tube catheter, such as a hemo-dialysis catheter, has first and second tubes which are attached to each other over a zone by one or more longitudinally extending wires which joins the two tubes over that zone. When a catheter is implanted in the patient, the attached zone is within the patient so that the catheter cannot be removed or advanced. When the catheter is to be removed, the longitudinally extending wire or wires are pulled proximally out of the tubes involved so that the two tubes can be separated and individually removed. A flexible separating prong within the patient and proximal of the zone holds the tubes apart to further assure that the catheter cannot be moved.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional application of Ser. No. 09/989,261filed on Nov. 20, 2001 now U.S. Pat. No. 7,347,852, the entire contentsof which is hereby incorporated by reference and to which priority isclaimed.

BACKGROUND OF THE INVENTION

This invention relates in general to a device and method for retaining acatheter in a patient and more particularly to the retention of a dualtube hemo-dialysis catheter.

DESCRIPTION OF PRIOR ART

Dual tube hemo-dialysis catheters are used to provide long term accessto the venous system. The catheter contains two lumens. One lumen forwithdrawal, and one lumen for return blood flow. Hemo-dialysisfiltration machines are connected to the catheter at regular intervalssuch as every other day. The patient's blood is removed, filtered, andreturned to the patient. A catheter of this design is described by Ashet al. in U.S. Pat. No. 5,947,953. These catheters must be fixed to thepatient to prevent the catheter from pulling out or advancing into thepatient. The most common method is to tunnel the catheter from the pointof venous access towards a remote location where the catheter is broughtout of the skin. This tunnel may be from 5-20 cm long. A Dacron cuffattached to the catheter shaft is located within the tunnel. The cuffprovides a porous area, which the patient's tissue grows into, providingan anchoring means. The cuff method is described by Martin et al. inU.S. Pat. No. 5,053,023. The catheter also may be sutured to the patientat the exit site by a “purse string” suturing technique.

Another method of fixing a catheter to the patient to prevent pullingout is to provide a bifurcation which is buried in the subcutaneoustissue. The bifurcate is located just outside of the catheters entranceto the vein. This design is described by Schon et al., in U.S. Pat. No.5,718,692. The Schon catheter contains two tubes brought together toform a bifurcation. The proximal ends of the tube are split apart andare tunneled separately to a remote location where they are broughtthrough the skin surface. The tissue between the proximal tube legsforms an anchor. If the catheter is pulled on, it cannot come outwithout pulling through the tissue. The catheter cannot advance due tothe hub that joins the two tubes. This method provides better catheterretention than the tunneled and cuffed designs.

Problems with Prior Art

When it is desired to remove these catheters, which may be after aperiod of two years in place, both of the above discussed methods havetheir downfalls. In both cases, it is necessary to perform minor surgeryto loosen the catheter. The tunneled and cuffed catheters require thecuff to be transected from the surrounding tissue. The bifurcated designrequires the site above the bifurcation to be opened, the tissuecarefully picked away from the catheter and the catheter to be removedin the reverse method from its installation. This is time consuming anddangerous. If the catheter is inadvertently cut, it can easily breakduring removal.

Objects

Accordingly, it is a major object of this invention to provide amultiple tube catheter design, of which a hemo-dialysis catheter is aprominent example, wherein the catheter design provides an enhancedtrade-off of effective anchoring in the patient with ease of removal bya doctor.

It is a related purpose of this invention to provide this ease ofremoval without requiring surgery to loosen the catheter for the purposeof removing the catheter.

It is a further related object of this invention to provide thisimproved multiple tube catheter in a design which readily adapts tocurrently employed techniques for catheter insertion.

It is a further related object of this invention to provide the aboveobjects in a fashion that avoids substantial increased costs in productor procedure.

It is a further related object of this invention to provide the aboveobjects in a device that does not require the cutting or dissection oftissue to remove the catheter and thus reduces the trauma and discomfortto the patient.

BRIEF DESCRIPTION

In brief, a multiple tube catheter is assembled so that in a zone of thecatheter near the mid-point of the tubes, the tubes are longitudinallyjoined together. Along this zone, the sidewall of one tube is connectedto the sidewall of the other. The attachment is achieved by a threadwhich in a preferred form is a wire. The wire attaches the two tubestogether by a technique analogous to that of sewing or stapling orotherwise having the wire or thread extend between the sidewalls of thetwo tubes.

The proximal end of the thread or wire extends within the sidewall ofone of the tubes to a point outside of the patient. Access can be had tothe proximal end of the wire by the medical professional who can pullthe wire free from the two tubes that are connected together by thewire. After the wire has been pulled free, the two tubes can beindividually removed from the patient. This procedure requires little orno surgical removal or cutting of tissue.

In a preferred embodiment, the two tubes have adjacent flat surfaces andtwo threads or wires are used in parallel. In that preferred embodiment,a separating prong, slightly proximal of the attachment zone extendsoutwardly from the surface of one of the tubes to engage the surface ofthe other tube to force the tubes to diverge away from one anotherproximal to said zone. This assures that there is a predeterminedbifurcation of the tubes within the patient's body thereby assuring thatthe tubes are adequately affixed and anchored in the patient and cannotbe accidentally advanced or retracted. Growth of bodily tissues into thespace between the tubes and the prong provides further anchoring.

DEFINITION

In preferred embodiments, a stainless steel surgical wire having adiameter of approximately 10 mils (0.010 inches) is used. However,elements other than a metallic wire can be used including, for example,a surgical suture.

Accordingly, it should be understood that in the claims, the term “wire”is used to cover not only the preferred metal wire but also whateverother sutures or threads or the like might be employed in the same orcomparable geometric structures to hold the two tubes together in useand by withdrawal to permit parting of the two tubes when use is over.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates the positioning of a two tubehemo-dialysis catheter in the jugular vein. In FIG. 1, the tubes arebrought exterior of the patient at points A. The two tubes are connectedat a zone B.

FIG. 2 is a perspective illustration of the invention showing the twotubes 10, 12 of the catheter which are in full contact with one anotherat a zone 14. A separating prong 16 is shown proximal of that zone.

FIG. 3 is a perspective illustration of a first embodiment of thisinvention in which a center segment is shown in longitudinal section.FIG. 3 shows a wire 26 contained in the sidewall of the first tube 22,the wire being stitched into the sidewall of the second tube 20 in thearea 24 where the two tubes are adjacent and stitched back into thesidewall of the first tube. FIG. 3 includes an expanded view of a smallproximal segment of the sidewall of the tube 22 to more clearly showwhere the distal end of the wire 26 terminates within the sidewall;which is at a location exterior of the patient.

FIG. 4 illustrates the center segment of the FIG. 3 embodiment on alarger scale. FIG. 4 is a longitudinal sectional view and more clearlyshows the wire 26 being stitched between the sidewalls of the two tubes20, 22 and also shows the wire 22 extending through the end of theseparating prong 28.

FIG. 4A is a cross-sectional view along the plane A-A of FIG. 4 andshows that two separate parallel wires 26 are employed. FIG. 4A is across-section through the separating prong 28 and shows that the wiresare passed through the prong.

FIG. 4B is a cross-sectional view along the surface B-B of FIG. 2 andillustrates the stitching of the upper tube 20 to the lower tube 22 bythe two wires 26.

FIG. 4C is a cross-sectional view of an alternative design separatingprong 28 along plane A-A. FIG. 4C shows two wires 29 which reinforce theseparating prong.

FIG. 5 illustrates a second embodiment of the invention. FIG. 5 is alongitudinal sectional view showing a wire 36 extending through a dovetail juncture 34 of the two tubes 30, 32.

FIG. 5A is a cross-sectional view along the plane A-A of FIG. 5 andillustrates an arrangement at that plane which is the same as that ofthe FIG. 4 embodiment.

FIG. 5B is a cross-sectional view along the plane B-B of FIG. 5illustrating the two wires 36 that extend through the dove tail joiningof the two tubes.

FIG. 6 is a longitudinal sectional view showing a third embodiment ofthis invention to which the two tubes 40, 42 are joined along alongitudinal lap joint 44. A single wire 46 is used to stitch the twotubes together.

FIG. 6A is a cross-section through the plane A-A of FIG. 6. Thiscross-section shows the separating prong 48 and illustrates that onlyone wire 46 is employed in this embodiment.

FIG. 6B is a cross-section along the surface B-B of FIG. 6 illustratinghow the wire 46 that joins the two tubes together is threaded throughthe lap joint 44.

FIG. 7 is a longitudinal cross-sectional view of a fourth embodiment inwhich a suture 56 is used to stitch two tubes 50, 52 together at thezone 54 where they are adjacent to one another.

FIG. 8 is a longitudinal cross-sectional view of a fifth embodiment,similar to the fourth embodiment, where a suture 66 is employed in afashion slightly alternate to that of FIG. 5 to stitch the two tubes 60,62 together at the zone 64 where they abut one another.

FIG. 9 is a longitudinal cross-sectional view of a sixth embodimentwhich employs a loop and pin method of coupling the wires 76, 78 in thesidewalls of the two tubes 70, 72 at the zone of juncture 74.

FIG. 9A is a cross-sectional view along the plane A-A of FIG. 9 andshows the wire 78 passing through an end of the separating prong 80.

FIG. 9B is a cross-sectional view along the surface B-B of FIG. 9 andshows a loop 82 which is attached to the loop wire 76 and loops aroundthe anchor wire 78.

FIG. 10 is a somewhat fanciful transparent perspective view of the FIG.9 embodiment to more clearly illustrate the loop and pin arrangement ofcoupling wires 76, 78 in the sidewalls of the two tubes 70, 72.

FIG. 11 illustrates what happens when the anchor wire 78 in the FIG. 9embodiment is removed thereby uncoupling the anchor wire 78 from theloops 82 of the loop wire 76 so that the two tubes 70, 72 are no longerjoined and can be removed from the patient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a first tube 4 and second tube 5 of a dual tube catheterplaced in relative position in the jugular vein 6 of a patient. The twotubes 4, 5 emerge from the patient at the points A.

As is known in the art, various fittings 7, 8 are shown. The fittings 8are used to connect the catheter to the rest of the dialysis processingsystem. Blood flow through the vein 6 is in a downward direction. Thelumen in tube 4 is the return lumen and the lumen in tube 5 is theaspiration lumen. The technique of implanting this type of catheter iswell known in the art and one technique is described in the Schon U.S.Pat. No. 5,718,692.

FIG. 2 illustrates the catheter device of this invention generically inwhich a first tube 10 and a second tube 12 are joined together at a zone14 by one of the techniques described herein. A separating prong 16 ispositioned proximal of the zone 14 assuring an appropriate separation ofthe two tubes 10, 12.

The embodiment shown in FIGS. 3 and 4 illustrates a first tube 20 and asecond tube 22 joined together at a zone 24 by wires 26. FIGS. 3 and 4show one of the two wires 26. Both of the wires 26 can be seen in thecross-sectional views of FIG. 4A and FIG. 4B. Each of the wires 26extends within a proximal portion of the sidewall of the tube 22. Eachwire 26 is threaded into the sidewall of the tube 20 and then back intothe sidewall of the tube 22. In this fashion, the two tubes 20, 22 areheld together by the two wires 26. FIG. 4C illustrates an alternativedesign prong 28 which is reinforced by two wires 29.

When the catheter is to be removed, access is had to the wires 26 at theproximal ends of the tubes 20, 22. The tube 22 is cut at the area 27(see the expanded element in FIG. 3) so that access can be had to theproximal end of each wire 26. The wires 26 are pulled out of the tubes20, 22 and must be pulled proximal of the opening 22R in the end of theseparator prong 28. Once that has been done, the two tubes can beseparately removed without requiring cutting a patient's tissue.

The separator prong 28 is a relatively thin flexible prong which willreadily flex during removal without causing significant tissue trauma.It has an end which fits into recess 22R. The prong may be reinforcedwith metal to prevent tearing of the polyurethane.

As may be seen in FIG. 4B, the two tubes 20 and 22 are formed so that atthe zone 24, they have flat surfaces which abut against one another.

As may be seen in FIGS. 2 and 4, the “bread-loaf” or tunnel likecross-section for the tubes 20 and 22 is maintained some distanceproximal of the zone 24. The tubes 20, 22 transition to the usualcircular cross-sections distal of the zone 24.

The separator prong 28 extends into the wall of the tube 22 at therecess 22R. The end of the prong 28 has two openings through which thewires 26 pass. This aids in maintaining rigidity for the prong 28 whenthe catheter is in use. The wires 26 have to be pulled proximally by atleast enough to clear the prong 28 in order for the tubes 20, 22 to befully separated.

FIG. 5 illustrates a second embodiment of the invention in which the twotubes 30, 32 are adjacent to one another along a zone 34 that provides adove tail engagement between the two tubes. In this embodiment, thejoining wires 36 extends through the teeth of both crenellated sectionsof the dove tail joint 34. The relatively thin flexible prong 38 extendsfrom the wall of the tube 30 and has an end which fits into a recess inthe wall of the tube 32. As in other embodiments, the joining wires 36extend through openings in the end of the prong 38. The removal of thewires 36 and the separation of the tubes 30 and 32 is the same as in theembodiment of FIGS. 3 and 4.

The FIG. 6 embodiment is similar to the other embodiments in that thereare two tubes 40, 42 having flat surfaces adjacent to one another alonga zone 44 and having a separating prong 48. The key distinction in FIG.6 is that the adjacent surface 44 is a longitudinal lap joint and thereis only a single joining wire 46. The wire 46 is threaded between thetwo portions of the lap joint 44, as shown in FIG. 6B, in a fashion thatmeans the wire 46 is, in this embodiment, not within a singlelongitudinal plane. The manner in which the wire 46 is threaded from theupper tube 40 into the lower tube 42 along the surface B-B is mirroredby the manner in which it is threaded from the lower tube 42 into theupper tube 40 at a position 49 proximal of the surface B-B.

FIGS. 7 and 8 indicate two other embodiments in which suture materialcapable of being used for surgical stitching is used. In FIG. 7, thesuture 56 extends through the sidewall of the lower tube 52 to the zone54 where the two tubes are adjacent to one another. At point 54A, thesuture is threaded into the sidewall of the upper tube 50 to returnproximally within the sidewall of the upper tube 50 until it exits atthe point 54B. It passes within the sidewall of the lower tube 52, upthrough the prong 58 and then proximally through the sidewall of theupper tube 50.

The FIG. 8 embodiment is very similar to the FIG. 7 embodiment in whichthe upper tube 60 and lower tube 62 are joined together at the adjacentsurface 64 by a suture 62 that doubles back within the wall of the uppertube 60; the one having the prong 68.

FIG. 9 illustrates a sixth embodiment in which first and second tubes70, 72 are deployed adjacent to one another along flat faces 74. A firstwire 76, called herein a loop wire, is contained in the wall of the tube72. A second wire 78, called herein an anchor wire is contained in thewall of the other tube 70.

As may best be seen in FIG. 10, when the catheter is in use, the anchorwire 78 extends through two loops 82 which in turn are soldered to theloop wire 76. This connection holds the two tubes 70, 72 togetherbecause the wires 76, 78 are contained within the sidewalls of the tubes70, 72.

When it is desired to remove the tubes from the patient, the two tubesare separated to facilitate such removal. The anchor wire 78, asillustrated in FIG. 11, is accessed by a medical professional andwithdrawn from the tube 70. This disconnects the anchor wire 78 from theloops 82 and the two tubes 70, 72 can be separated and handledindividually.

It might be noted, that the distal portion of the two tubes in eachembodiment is circular in cross-section. To assure that the two tubesare adjacent to one another along a flat surface, the two tubes areformed to have a bread-loaf or tunnel-like cross-section in the zone ofcontact.

Numerous embodiments of this invention have been disclosed in order toillustrate the scope of the inventive concept. However, one skilled inthe art can apply this concept to other embodiments.

For example, although it is clearly preferred that the tubes be adjacentalong a flat surface, the inventive concept can be employed with twotubes in contact along a circular cross section and thus adjacent onlyalong a line. Such an embodiment might require that the coupling wire orthread be exposed when extending from one tube to the adjacent tube.

In most embodiments, the preferred format is to have two wires orthreads connecting the adjacent tubes. However, a single wire or threadcan be used, although at the present time, such is not preferred in mostembodiments.

In all embodiments, it is preferred as shown in FIG. 3, that theproximal ends of the wire are sealed into the catheter so that when thetubes are to be removed, the proximal ends of the tubes are cut at anappropriate point and access can be had to the wire to pull the wirefree so that the tubes can be separated. This proximal sealing of thewire can be done after the wire has been threaded into the tubes.

Plastic tubes of the sort depicted in the various embodiments can bereadily molded with the lumen depicted and with the longitudinalopenings of the sidewalls for receipt of the wire. The wire is typicallyassembled in the two tubes by being passed through a longitudinal lumenwithin the sidewall of one tube and threaded into a similar lumen in theother tube. The wire and tubes are flexible enough so that thisthreading can be readily achieved.

In one typical embodiment, the following parameters are employed. Thetubes are made of a polyurethane material and have a diameter of 120mils and a sidewall thickness of 20 mils. The wire is spring temperstainless steel, Teflon coated. The wire ends are slightly tapered tocreate a stiffness transition. The longitudinal sidewall lumens toreceive the wire are approximately 15 mils; enough to provide a veryeasy slip fit relationship with a 10 mil wire. The prong is 50 milsthick, by 70 mils wide and extends for a length of approximately 200mils.

1. The method of retaining and removing a catheter tube in a patientcomprising the steps of: implanting a catheter having a zone in whichthe catheter tube and a companion member are stitched together with alongitudinal wire that extends longitudinally within the sidewalls ofthe tube and the companion member along said zone wherein said zone ispositioned in the patient and the wire extends to a point outside thepatient, said zone retaining the catheter in the patient, and removingthe catheter by accessing a proximal portion of said wire, withdrawingsaid wire and individually removing the catheter tube and the companionmember.
 2. The method of retaining and removing a multiple tube catheterin a patient comprising the steps of: implanting a catheter having azone in which at least two tubes are stitched together with alongitudinal wire that extends longitudinally within the sidewalls ofsaid tubes along said zone wherein said zone is positioned in thepatient and the wire extends to a point outside the patient, said zoneretaining the catheter in the patient, and removing the catheter byaccessing a proximal portion of said wire, withdrawing said wire andindividually removing each of said tubes.
 3. The method of retaining andremoving a multiple tube catheter in a patient comprising the steps of:implanting a catheter having a zone in which at least two tubes arestitched together with a longitudinal wire wherein the zone ispositioned in the patient and the wire extends to a point outside thepatient, said zone retaining the catheter in the patient, and removingthe catheter by accessing a proximal portion of said wire, withdrawingsaid wire and individually removing each of said tubes, wherein duringsaid step of implanting the catheter, providing a separating flexibleprong proximal of said zone extending from a first one of said tubesinto a recess on the second one of said tubes to hold said tubes apartto prevent distal movement of the catheter, and during said step ofremoving the catheter, removing said prong from said recess.
 4. Themethod of implanting and removing a multiple tube catheter implanted ina patient comprising the steps of: providing a multiple tube catheterassembly, having first and second tubes and a wire extendinglongitudinally within the sidewalls of said tubes along a predeterminedzone and passing through contacting surfaces of said tubes at said zoneto hold said tubes together at said zone, said wire extending proximallywithin the sidewall of said first one of said tubes to a predeterminedproximal position, implanting said assembly in a patient with said zonewithin the patient and the proximal ends of said wire extending outsideof the patient, accessing the proximal end of said wire, removing saidwire from said catheter to disconnect said tubes at said zone, and thenindividually removing each of said multiple tubes from the patient. 5.The method of claim 4 wherein said step of removing comprises pulling onsaid wire.